GCORPHA (May96)              ftools.caltools             GCORPHA (May96)



NAME
    gcorpha -- remaps PHA channels from SPECTRUM extension.
    
    
USAGE
    gcorpha infil shftfil outfil
    
    
DESCRIPTION
    
    This task remaps PHA channels according as defined by user.
    
    Given  an  OGIP-approved  FITS format input file, this task provides
    the  facility  to  move  the  user-defined  PHA   channel   elements 
    (columns)  of  the  array  to  the  left  or right (ie down or up in
    channel-space) by a user-defined number of channels.
    
    The shift to be applied to each channel of the  input  PHA  channels
    must  be specified by an ASCII input file. The format of each row of
    this input ASCII file must be
                           MINCHAN MAXCHAN NCHAN
    denoting all 'columns' of the  i/p  PHA  channels  between  detector
    channels  MINCHAN  and  MAXCHAN  (inclusive)  are  to  be shifted by
    NCHAN. The shift, NCHAN, can be a positive or  negative  INTEGER  or
    real  number  of channels (or zero). Any channel ranges "implied" by
    their exclusion  from  the  ASCII  file  will  be  shifted  by  zero
    channels.  Note  that  should  the  shift  applied  to  two  or more
    'columns' result in those columns being in  the  same  o/p  detector
    channel,  then  their  respective  probabilities  (that  an incident
    photon of a given energy will be detected in that detector  channel)
    WILL  BE  SUMMED.  Similarly, should the applied shifts result in an
    o/p  detector  channel  'column'  NOT  being  populated,  then   the 
    probability  (that  an  incident  photon  of  a given energy will be
    detected in that detector channel) will be set  to  zero.   However,
    shifts  below  the  minimum,  and  above  the  maximum legal channel
    number for the instrument will result in those  probabilities  being
    excluded.
    
    
WARNINGS ON USAGE
    
    
    
    

    PARAMETERS
    
    infil [character string]
         The name of the FITS PHA file to be remapped in channel-space
    
    outfil [character string]
         The name of the FITS file to be written containing the
        remapped PHA dataset
    
    shftfil [character string]
         The name of an ascii file specifying the remapping
        information. The ascii  file format should be of the form :
                                     1 20 -1
                                     21 30 0
         where  channels  1  to 20 are shifted back by one, and 21 to 30
        stay as they are.
    
    (chatter = 9) [integer]
         Flag to indicate how chatty the task is at execution.  A  value
        of  9  is  the   default,  with  lower/higher  values  producing 
        quieter/verbose output  respectively.
    
    (clobber = false) [boolean]
         Flag specifying whether or not a  pre-existing  file  with  the
        same  name  as that  requested as the output file from this task
        will be overwritten.
    
    
BUGS
    None known
    
    
    
SEE ALSO
    GCORRMF
    
    
LOG OF SIGNIFICANT CHANGES
    
    
    v1.0.0 (1996 June)
            Initial public release
    
    
PRIMARY AUTHOR
    
    Banashree Mitra Seifert
    HEASARC
    NASA/GFSC
    http://heasarc.gsfc.nasa.gov/cgi-bin/ftoolshelp
    (301) 286-5307